Fix: add executed to EOSIO_DISPATCH()

[b1aafulei]

Change Description

Related to Issue #868.

In the current code, EOSIO_DISPATCH_INTERNAL assumes the existence of boolean variable executed. There are two external entry points for that:

Path 1: EOSIO_ACTIONS --> EOSIO_DISPATCH_HELPER --> EOSIO_DISPATCH_INTERNAL
Path 2: EOSIO_DISPATCH --> EOSIO_DISPATCH_HELPER --> EOSIO_DISPATCH_INTERNAL

While executed is defined in EOSIO_ACTIONS, it is not defined in EOSIO_DISPATCH. This quick fix adds executed to EOSIO_DISPATCH (and does nothing else), so the assumption of the existence of executed now holds in both paths.